Rotary closed rankine cycle engine with internal lubricating system

ABSTRACT

A rotary closed Rankine cycle engine comprising a housing rotatable about its axis and including an annular boiler adapted to contain a liquid power fluid. The housing is subdivided into separate expander and lubricant compartments. The expander is actuated by pressure vapor power fluid generated in the boiler and rotationally drives a coaxial shaft associated with other moving parts. An annular sump is provided in the lubricant compartment adapted to contain an annular lubricant bath of predetermined radial depth. Non-rotatable pump means is provided in the lubricant compartment operable by rotation of the housing relative to the pump to pump lubricant from the bath to the shaft and associated moving parts to lubricate the same. Heating means is provided for vaporizing excess power fluid that migrates along the shaft from the expander compartment to the lubricant compartment thereby raising the vapor pressure in the lubricant compartment to the vapor pressure in the expander compartment and balancing the pressure along the shaft to prevent further migration of power fluid from the expander compartment to the lubricant compartment. This invention relates to new and useful improvements in rotary heat engines, and more particularly to closed Rankine cycle engines of the rotating type having novel means for lubricating the internal moving parts of the engine. One of the problems in the design of closed Rankine cycle engines is the lubrication of the internal moving engine parts and this is especially true in closed Rankine cycle engines of the rotating type. When internal moving engine parts such as bearings, gears, and the like are lubricated in a conventional manner with oil or grease, it is necessary to isolate the power fluid from the lubricant to prevent the lubricant from being washed away and diluted by the power fluid. Complete separation of the power fluid and lubricant is very difficult, if not impossible, to provide and maintain. For this reason a common approach to the probelm has been to use a power fluid having properties that also provide lubrication for the internal moving parts of the engine. However, while this approach has met with some degree of success in Rankine cycle engines of the non-rotating type, there is no available power fluid having adequate lubricating properties that provides the efficiency and stability required for satisfactory operation of a rotating closed Rankine cycle engine. On the other hand, the use of a separate lubricant for the moving parts of a rotating closed Rankine cycle engine presents the probelm and difficulty of effectively isolating the power fluid from the lubricant. This could be accomplished to a resonable degree by the use of high speed seals but, apart from the complication and cost of such seals, they are not a satisfactory solution to the problem primarily because they absorb substantial power from the engine and also because they cannot be made completely effective. With the foregoing in mind, an object of the present invention is to provide a rotating closed Rankine cycle engine having novel means for lubricating and cooling the internal moving parts of the engine. as set Another object of the invention is to provide a rotating closed Rankine cycle engine having novel lubricating means as set forth that does not require the use of high speed seals to effectively isolate the engine power fluid from tHe lubricant. A further object of the invention is to provide a rotating closed closed Rankine engine having novel lubricating means that may be effectively employed for lubricating the internal parts of the engine when the latter is rotationally driven internally directly from the primary power output of the engine or indirectly from an independent external source of rotary motion.

ilnited States Patent [1 1 Doerner [111 3,744,246 [451 July 10, 1973ROTARY CLOSED RANKINE CYCLE ENGINE WITH INTERNAL LUBRICATING SYSTEM [75]lnventor: William A. Doerner, Wilmington,

Del.

[73] Assignee: E. I. du Pont Nemours and Company,

Wilmington, Del.

22 Filed: Mar. 2, 1972 21 Appl. N0.: 231,232

[52] U.S. Cl 60/95, 60/108, 122/11, 415/18, 415/122, 308/106 [51] Int.Cl. F01k 11/04 [58] Field of Search 60/36, 108, 95; 122/11 [56]References Cited UNITED STATES PATENTS 12/1938 Starziczny 60/108 R10/1957 Ball 7/1966 Anderson 60/108 R X Primary Examiner-Martin P.Schwadron Assistant Examiner-H. Burks, S'r.

Att0rneyDexter N. Shaw, Charles H. Howson, Jr. et a1.

[5 7 ABSTRACT A rotary closed Rankine cycle engine comprising a housingrotatable about its axis and including an annular boiler adapted tocontain a liquid power fluid. The housing is subdivided into separateexpander and lubricant compartments. The expander is actuated bypressure vapor power fluid generated in the boiler and rotationallydrives a coaxial shaft associated with other moving parts. An annularsump is provided in the lubricant compartment adapted to contain anannular lubricant bath of predetermined radial depth. Non- 1 rotatablepump means is provided in the lubricant com- 7 Claims, 4 Drawing Figures1 3,744,246 1 July 10, 1973 United States Patent [1 1 Doerner PATENIEDJUL 1 W975 manure closed Rankine cycle engines of the rotating typehav-.

ing novel means for lubricating the internal moving parts of the engine.

One of the problems in the design of closed Rankine cycle engines is thelubrication of the internal moving engine parts and this is especiallytrue in closed Rankine cycle engines of the rotating type. When internalmoving engine parts such as bearings, gears, and the like are lubricatedin a conventional manner with oil or grease, it is necessary to isolatethe power fluid from the lubricant to prevent the lubricant from beingwashed away and diluted by the power fluid. Complete separation of thepower fluid and lubricant is very difficult, if not impossible, toprovide and maintain. For this reason a common approach to the probelmhas been to use a power fluid having properties that also providelubrication for the internal moving parts of the engine.

However, while this approach has met with some degree of success inRankine cycle engines of the nonrotating type, there is no availablepower fluid having adequate lubricating properties that provides theefficiency and stability required for satisfactory operation of arotating closed Rankine cycle engine. On the other hand, the use of aseparate lubricant for the moving parts of a rotating closed Rankinecycle engine presents the probelm and difficulty of effectivelyisolating the power fluid from the lubricant. This could be accomplishedto a resonable degree by the use of high speed seals but, apart from thecomplication and cost of such seals, they are not a satisfactorysolution to the problem primarily because they absorb substantial powerfrom the engine and also because they cannot be made completelyeffective.

With the foregoing in mind, an object of the present invention is toprovide a rotating closed Rankine cycle engine having novel means forlubricating and cooling the internal moving parts of the engine. as setAnother object of the invention is to provide a rotating closed Rankinecycle engine having novel lubricating means as set forth that does notrequire the use of high speed seals to effectively isolate the enginepower fluid from the lubricant.

A further object of the invention is to provide a rotating closed closedRankine engine having novel lubricating means that may be effectivelyemployed for lubricating the internal parts of the engine when thelatter is rotationally driven internally directly from the primary poweroutput of the engine or indirectly from an independent external sourceof rotary motion.

These and other objects of the invention and the various features anddetails of the construction and operation thereof are hereinafter setforth and described with reference to the accompanying drawings, inwhich:

FIG. 1 is a typical fragmentary sectional view diametrically through arotary closed Rankine cycle engine embodying the present invention;

FIG. 2 is a schematic view on line 22, FIG. 1;

FIG. 3 is a fragmentary sectional view similar to FIG. 1 showing anotherengine embodiment of the present invention; and

FIG. 4 is a fragmentary transverse sectional view on line 4-4, FIG. 3.

Referring now to the drawings, and more particularly to FIG. 1 thereof,there is disclosed a rotary closed Rankine cycle engine embodying thepresent invention that comprises a housing H including a boiler B, asuitable expander such as, for example, a turbine T, a rotary condenserC coupled to the boiler for rotation therewith as a unit, and meansdriven by the expander and connected to the boiler-condenser unit torotationally drive the latter at a predetermined speed, as hereinafterset forth and described.

In the embodiment of the invention shown in FIG. 1 of the drawings, therotary housing H and boiler B is constructed and operable, for example,substantially as shown and described in my U. S. Pat. No. 3,613,368issued Oct, 19, 1971. Such a housing and boiler comprises a cylindricalchamber 1 defined by an outer continuous circumferentially extendingwall 2, side walls 3 and 4, and an inner cylindrical wall 5. The boilerchamber wall 3 extends radially inward and is and is at its inner end toan annular hub structure 6 disposed coaxially with respect to andinternally of the boiler B. The hub 6 has a central bore 7 extendingaxially therethrough and mounted coaxially in the outer end thereof is ashaft 8 that is securedin the hub 6 for rotation therewith. The shaft 8is rotatably joumalled in a bearin 9 that is mounted in a fixed standardor support 10.

The inner cylindrical wall 5 of the boiler is fixedly secured to theperipheral portion of the adjacent surface of a radially extendingcoaxially circular plate or disk 12 that projects outwardly from theinner end of a coaxially extending tubular shaft 13. The tubular shaft13 and plate 12 are rotatably mounted by means of a bearing 14 upon acoaxially extending stationary shaft 16 that has its outer end suitablysupported coaxially of the engine.

The rotary boiler is adapted to be driven about its axis at apredetermined speed of rotation calculated to create the centrifugalforce necessary to dispose and maintain the selected boiler liquidtherein uniformly distributed circumferentially about and in contactwith the inner surface of the outer peripheral wall 2 of the boiler witha liquid/vapor interface, designated x in FIG. 1, that is highly stableand essentially cylindrical and concentric with the axis of rotationwith the boiler, Essentially the liquid/vapor interface x is disposed ata predetermined radius from the rotation axis of the boiler to providehigh boiling heat fluxes in excess of those obtainable at ambientgravity. The annular body of liquid in the boiler may be heated to therequired boiling temperature to vaporize the same, for example, by thecombustion of a suitable fuel-air mixture in a stationary combustion box21 that may be constructed and arranged about the boiler as shown anddescribed in my aforesaid patent;

The expander, in the form of a turbine T, constructed and operable, forexample, generally as shown and described in my aforesaid U. S. Pat. No.3,613,368, comprises a rotor 22 having a series of turbine blades 23arranged peripherally thereabout. The turbine rotor 22 is receivedwithin an annular recess 24 provided in the hub structure 6 and ismounted for coaxial rotation independently of the boiler B on a shaft 25that is rotationally supported within bore 7 of the hub 6 by means ofbearings 26. An annular series of nozzles 27 is provided in the hub 6coaxially adjacent the turbine rotor 22 in confronting relation to theblades 23 thereof and high pressure vapor is supplied to the nozzles 27from an annular manifold 28.

High pressure vapor is supplied from the boiler chamber 1 to themanifold 28 by a plurality of vapor tubes 29 arranged in equally spacedrelation circumferentially of the axis to insure rotational balance inthe boiler. The high pressure vapor discharged from the manifold 28through the nozzles 27 impinges upon the blades 23 to drive the turbinerotor 22 and its shaft 25 at the desired speed of rotation. A no-contactlabyrinth seal 30 is provided about the shaft 25 inwardly adjacent theturbine rotor 22 to reduce migration of the pressure vapor from theturbine along shaft 25.

An annular diffuser 31 is provided in the hub 6 to receive the exhaustvapor from the expander, such as turbine T, and discharge it into anannular exhaust chamber 32 from which it passes into the condenser C. Aplurality of axially extending radial partitions or baffles 33 isprovided in the exhaust chamber 32 and arranged in equally spacedrelation circumferentially about the engine axis to maintain the angularvelocity of the exhaust vapor at that of the rotating boiler-condenserunit and to direct the vapor toward and into the condenser C.

In the illustrated embodiment of the invention the condenser C isconstructed and operable as shown and described in my aforesaid U. S.Pat. and in my copending US. Pat. application Ser. No. 110,478, filedJan. 28, 1971. Thus, the condenser C comprises a coaxial array ofannular radial fins 34 and axial heat exchange tubes 35 mounted forrotation with the boiler B, plate 12 and shaft 13as a unit. The centralportion of the plate 12 curves inwardly and endwise to the shaft 13, asindicated at 36, to provide a smooth curvilinear surface for directing acooling fluid, such as air, outwardly through the condenser fins 34. Theturbine exhaust vapor discharged to the chamber 32 passes into the heatexchange tubes 35 where it is condensed by heat exchange with a coolingfluid, and then flows into an annular collector 37 from which it isdischarged radially by centrifugal force generated by rotation of thecondenser C, through a plurality of conduits 38 and returned to theboiler chamber 1.

The boiler-condenser unit is rotationally driven continuously by theprimary power output generated by the engine by means of an internaloccluded fixed-ratio gear train arranged coaxially of the engine axisand interiorly of the rotary boiler-condenser unit. In the embodiment ofthe invention shown in FIGS. 1 and 2, the gear train comprises a sungear 40 fixedly mounted on and driven by the turbine shaft 25. Meshedwith the sun gear 40 is a plurality of planetary gears 41 that are alsomeshed with a circumscribing annular ring gear 42 fixedly mounted on andcarried by an annular flange 43 that is formed integral with andprojects axiallyinward from the adjacent face of the palte l2. lnthepresent embodiment, three planetary gears 41 are provided and arrangedin equally spaced relation circumferentially about the engine axis. Eachof the planetary gears 41 is rotatably mounted on a stub shaft 44 bymeans of a bearing 45 and each stub shaft 44 is fixedly mounted in astationary spider portion 46 provided at the the stationary end ofthestationary shaft 16. The stationary spider 46 functions as a torqueanchor and opposes the reaction torque generated by the engine. By thisconstruction the axes of the planetary gears 41 are fixedly positionedso that they do not rotate or move circumferentially relative to orabout the engine axis. Thus, the full power output of the engineexpander is transmitted from the driving sun gear 40 through theplanetary gears 41 directly to the driven ring gear 42 on theboiler-condenser unit at the fixed-speed ratio of the particular geartrain.

However, it will be apparent that at start-up there will be no pressurevapor generated by the boiler B to drive the turbine and in turn theboiler-condenser unit. Consequently, at start-up it is necessary toindependently drive the boiler-condenser unit at the designedpredetermined speed of rotation to establish and maintain theliquid/vapor interface x in the boiler chamber 1 until the annular bodyof liquid in the boiler is heated to the temperature to produce thedesired pressure vapor to drive the turbine rotor 22. This may beaccomplished, for example, by means of a starter motor M driving apulley 7t) fixed on the engine shaft 8 through abelt or chain 71. Meanssuch as a clutch (not shown), can be provided for breaking the drivebetween motor M and pulley when the engine attains normal operation, orthe motor can continue to be driven by the shaft 8 to function as agenerator operable, for example, for charging a battery that powersaccessories such as the starter motor, lights and the like.

In accordance with the present invention, the various moving parts ofthe engine are lubricated by a force feed system utilizing a Pitot typepump. As shown in FIG. 1 of the drawings, the plate 12 andflange 43cooperate with the adjacent portion of the engine hub 6 to provide anannular lubricant sump 48 having a fill and drain plug 49. In theembodiment shown, the ring gear 42 of the fixed-ratio gear train, beingmounted on the flange 43 as previously described, is disposed in thesump 48. The Pitot pump comprises a radial passage 50 formed in thestationary spider 46 and having at its outer end an L-shaped tip 51, theinlet end of which is immersed in an annular bath of lubricant 52 in thesump 48, with the inlet thereto facing opposite the di rection ofrotation of the engine. The predetermined speed at which the boiler isrotationally driven to maintain the annular liquid body of power fluidin the boiler also maintains the annular lubricant path 52 in the sump48.

The inner end of the passage 50 is connected to a coaxial passage 53formed in the spider portion 46 and extending a short distance into theadjacent end portion of the shaft 16 where it connects with a radialpassage 54 that opens adjacent the bearing 14. A coaxial passage 55extends through the sun gear 40 and adjacent portion of the turbineshaft 25 where it connects with a radial passage 56 that opens betweenthe axially spaced bearings 26. Connection between the nonrotatingpassage 53 and the passage 55 in the rotating sun gear 40 is made bymeans of a connector tube 57 that has one end fixed in the passage 55for rotation with the sun gear 4! and the other end mounted coaxiallywithin the stationary passage 53 by means of a screw seal 58, forexample, asshown in FIG. 1.

Rotation of the engine relative tothe non-rotating spider 46 operates topump lubricant from the bath 52 inwardly of the tip 51 and through thepassage 50 and the connecting passages to the bearings 14 and 26. Sincethe ring gear 42 is immersed in the annular bath of lubricant as shownin the drawings, the gears 40 and 41 will be lubricated by contact withthe ring gear and the lubricant picked up by gears 40 and 41 will flowradially over the said gears and return to the sump. In the case wherethe ring gear 42 is not in the lubricant bath 52, the gears may beeffectively lubricated by providing a radial passage (not shown) in thesun gear 40 leading from the axial passage 55 and opening to the teethof the sun gear that is meshed with the planetary gears 41. Lubricantsupplied to the gears and bearings drains back to the bath 52 in thesump 48 under the influence of centrifugal force.

The lubricant sump 48 is ideally located close to the condenser C sothat it will be as cool as possible. To this end the sump 48 isthermally isolated from the hot turbine parts of the engine by annularvoids or spaces 59 and 60 provided therebetween and the lubricant bath52 in the sump is also cooled by contact with the curved portion 36 ofthe housing plate 12 that in turn is cooled by contact with the heatexchange fluid (air) flowing through the condenser C. A sleeve or collar61 on the stationary spider 46 extends axially therefrom incircumscribing relation about the inner end of the rotatable tubularshaft 13 to collect lubricant that drains from the bearing 14 and directit over the inner surface of the air-cooled portion 36 of plate 12 sothat it is further cooled en route back to the sump 48. In addition, thesump 48 and bath of lubricant are further thermally isolated from thehigh temperature in the turbine exhaust chamber 32 by means of anannular barrier 62 of suitable insulating material such as, for example,molded fiberglass that functions also to subdivide the interior of theengine housing into an expander compartment and a lubricant sumpcompartment.

A unique feature of the present invention is the construction andarrangement thereof that enables the use of separate power fluid andlubricant without the necessity of providing a positive high speed sealon the shaft 25 to prevent the migration of power fluid along the shaft25 from the turbine T to the lubricant sump 48. A typical example of asuitable power fluid that may be employed efflciently in the presentinvention is a mixture of the isomers of trichlorotrifluorobenzene andthe lubricant bath 52 in the sump 48 may comprise, for example, amixture of about equal parts by weight of the aforesaid power fluid anda lubricant material such as Krytox 143 fluorinated oil. Otherlubricants such as, for example, poly(phenyl ether) and Zonyl 1-3-7 and15-91 fluoroalkyl esters may also be employed. Alternatively, suitableamounts of finely divided graphite or finely divided molybdenumdisulflde might also be employed as the lubricant material in the bath52. In any event, it is necessary that the lubricant be stable at hightemperatures and have a very low volatility so as to minimize lossthereof from the lubricant bath 52 in the sump.

The flll and drain plug 49 may be used to supply the sump 48 with therequired amount of working fluid and lubricant mixture. Solubility ofthe lubricant in the working fluid of the bath 52 is not necessary sincethe stirring action caused by the rotational movement of the sumprelative to the pump tip 51 forms an emulsion or temporary suspension ofthe lubricant in the working fluid of the bath 52.

During operation of the engine, at least initially some of the powerfluid from the turbine T will migrate along the shaft 25 through theno-contact labyrinth seal 30 and find its way into the lubricant bath 52in the sump 48. This additional power fluid condensing in the lubricantin the sump 48 will increase the radial depth of the bath 52 and, inaccordance with the present invention, means is provided for distillingor vaporizing off the excess power fluid from the lubricant bath 52 whenthe latter attains a predetermined maximum radial depth.

In the illustrated embodiment of the invention, thisis accomplished byproviding in the hub structure 6 an annular chamber 63 of small radialdimension that extends axially laterally from the sump 48 and isdisposed radially from the engine axis a distance corresponding to thesurface level of the lubricant bath at the predetermined maximum radialdepth thereof. Thus, when migration of power fluid from the turbinealong shaft 25 to the sump 48 has increased the radial depth of the bath52 above the predetermined maximum depth, the mixture of lubricant andexcess power fluid will overflow from the sump into the chamber 63 whereit is heated to a temperature sufficiently high to distill and vaporizeoff the excess power fluid from the lubricant. The chamber 63 is heatedto the required temperature by hot pressure vapor from the boiler Bsupplied by tubes 64 to an adjacent circumscribing annular heatingchamber 65.

Heating the overflow from the sump 48 in the chamber 63 to distill orvaporize off the excess power fluid therein raises the vapor pressure inthe engine chamber 66 containing the sump and gear train to the vaporpressure at the turbine T thereby balancing the pressure across thelabyrinth seal 30 and precluding further migration of power fluid alongshaft 25 from the turbine T to the sump 48. This arrangement entirelyeliminates the need for a high speed seal on the shaft 25 which would benot only expensive but also consume substantial power and be difficultto make completely effective in preventing fluid flow.

The present invention is not limited in its use to rotary engines of theconstruction previously described in which the boiler-condenser unit isrotationally driven through an internal gear train directly from theprimary power output of the engine, and the invention may be employedeffectively for lubricating the internal moving parts of a rotary enginein which the boilercondenser unit is rotationally driven independentlyof the Rankine engine by a source of rotary power located externally ofthe engine.

An embodiment of an externally driven rotary engine employing thepresent invention is shown in FIGS. 3 and 4 of the drawings. Except forstructural differences hereinafter described, the apparatus seown inFIG. 3 is otherwise identical to the embodiment shown in FIG. 1 and,accordingly, elements and parts in FIG. 3 that are identical to elementsand parts in FIG 1 are identified by the same reference numbers andletters to avoid unnecessary repetition of description thereof.

Referring to FIG. 3, the engine housing, boiler, expander and condenserare constructed and arranged as previously described except that theinternal fixed-ratio gear train for driving the boiler-condenser unithas been eliminated and the boiler-condenser unit is continuously drivenat the desired predetermined speed of rotation by means of the motor Mdriving pulley 70 fixed on the engine shaft 8 through the belt or chain71. Also, the turbine shaft 25' is directly coupled to and rotationallydrives the coaxial shaft of the rotor R of a generator G mountedcoaxially within the condenser C and having its stator and windings Sfixedly secured to the engine housing H for rotation with theboilercondenser as a unit relative to the rotor R. Of course, othermachinery and equipment can be coupled to and driven by the turbineshaft 25' as desired.

1n the embodiment of the invention shown in FIG. 3 the internal movingengine parts are lubricated by a force feed system of the typepreviously described utilizing a Pitot pump incorporated in a pendulummember 75 having a hub portion 76 journalled on the turbine shaft 25' bymeans of bearings 77. The pendulum is of predetermined density anddimensions operable to hold the pendulum in the position shown andprevent rotation thereof about the engine axis during operation of theengine. As shown, the pendulum 75 depends radially and terminatesadjacent the operating surface level of the lubricant path 52' in thesump 48. In the present embodiment, the Pitot pump comprises a radialpassage 78 formed in the pendulum 75 and having at its outer end anL-shaped tip 51 The end of the tip 51 is immersed in the lubricant bath52' and the inlet to the tip is disposed facing in the directionopposite the direction of rotation of the boiler-condenser unit aspreviously described.

The inner end of the radial passage 78 in the pendulum is incommunication with a radial passage 79 in the turbine shaft 25' that inturn communicates with a coaxial passage 55' therein. The coaxialpassage 55' connects with a radial passage 56' that opens outwardlyintermediate the shaft bearings 26' and also connects with a radialpassage 54 that opens adjacent the bearing 14 in which is journalled theshaft of rotor R of the generator G. As indicated, but not fully shown,the passage 55' extends axially beyond the passage 54' to the other endof the shaft of rotor R to lubricate a bearing similar to bearing 14that rotationally supports the outer end of the rotor shaft. Duringoperation. of the engine. rotation of the boiler-condenser unit and sump48' relative to the stationary or non-rotating pendulum 75 operates topump lubricant from the bath 52' inwardly of the tip 51' and through thepassages 78, 79, 55', 56' and 54' to the bearings described. Lubricantthus supplied to the bearings drains back to the bath 52' in sump 48'under the influence of centrifugal force.

Apart from the differences described, operation of the engine embodimentshown in FIG. 3 is essentially the same as previously described and neednot be repeated.

From the foregoing, it will be observed that the present inventionprovides a novel lubrication system for closed Rankine cycle engines ofthe rotating type that enables the use of separate power fluid andlubricant and also eliminates the need for high speed seals to isolatethe power fluid from the lubricant.

While certain embodiments of the invention have been illustrated anddescribed, it is not intended to limit the invention to suchdisclosures, and it is contemplated that changes and modifications maybe made and incorporated as desired or required, within the scope of thefollowing claims.

I claim:

1. A rotary closed Rankine cycle engine comprising:

a cylindrical housing rotatable about its axis and including an annularboiler adapted to contain an annular body of liquid power fluid,

means to heat the liquid in the boiler to generate power fluid pressurevapor therein,

means subdividing the housing into an expander compartment and lubricantcompartment,

an expander in said expander compartment for extracting work from saidpressure vapor including a coaxially rotatable shaft driven thereby andextending into the lubricant compartment of the housing,

an annular sump in said lubricant compartment adapted to contain anannular lubricant bath of predetermined radial depth, means operable torotationally drive the housing and boiler about said axis at apredetermined speed to maintain the annular liquid bodies of power fluidand lubricant in the boiler and sump respectively,

pump means in the lubricant compartment nonrotatable with the housinghaving a lubricant passage extending inwardly from the lubricant bath tosaid shaft with the inlet to said passage immersed in the lubricant bathand facing opposite the direction of rotation of the housing wherebyrotation of said housing relative to said pump means operates to pumplubricant inwardly from the bath through the passage to lubricate saidshaft,

and means for heating and vaporizing excess power fluid that migratesalong the shaft from the expander compartment to the sump therebyraising the vapor pressure in the lubricant compartment substantially tothe vapor pressure in the expander compartmentand balancing the pressureaxially along the shaft to prevent further migration of power fluid fromthe expander compartment to the lubricant compartment of the housing.

2. A rotary engine as claimed in claim 1 wherein the means torotationally drive the housing and boiler comprises a fixed-ratio geartrain interconnected between the shaft and housing and lubricated bylubricant from the bath.

' ducting lubricant from the pump means to said bearings for lubricatingthe bearings.

4. A rotary engine as claimed in claim 1 wherein the means for heatingand vaporizing the excess power fluid migrating to the sump comprises anannular overflow chamber disposed laterally adjacent the lubricant sumpsubstantially at the surface level of the predetermined radial depth ofthe lubricantbath therein for receiving overflow of said lubricant bathcaused by said migration of power fluid to the sump, and means forheating the annular chamber to vaporize power fluid from the overflowlubricant bath therein.

5. A rotary engine as claimed in claim 4 wherein the means for heatingthe annular overflow chamber comprises a second annular chamberconcentrically circumscribing the overflow chamber, and means forsupplying hot pressure vapor power fluid from the boiler to said secondchamber.

6. A rotary engine as claimed in claim 2 wherein the fixed-ratio geartrain includes a plurality of planetary gears, and the non-rotatablepump means is a stationary member on which said planetary gears arerotatably mounted so that the axes of the planetary gears are fixedlypositioned circumferentially with respect to the rotational axis of theengine.

7. A rotary engine as claimed in claim 1 wherein the non-rotatable pumpmeans comprises a pendulum member journalled on the expander shaft andhaving a density and dimensions operable to hold said pendulum member independent position and prevent rotation thereof about the rotationalaxis of the engine.

l t II Patent No.

Dated July 10, 1973 Invent0r(x) line line

line

Col. 2, line line line

line

Col. 3, line line William A.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Col; 1, line 31; "probelm" should read -problem--.

lines 62 Doerner delete "as set".

delete "closed" (Second occurrence) after "Rankine" insert --cycle--.

delete "and is" (second occurrence) and substitute -connec ted--.

"securedin" should be --secured in--. "bearin" should read -bearing -i"with" should be -of-. (second occurrence) "palte" should be -plate--.

and 63; delete "the stationary" and insert inner--.

"thestationary" should read --the stationary--.

FORM PO-1050 (10-69) USCOMM-DC 60376-P69 u.s. sovsnuuzm PRINTING OFFICE:1969 osss-au,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PRIMH' Nn. W H

Dated J.. .Y .91

Inventor(K) William A. Doerner Page --2- It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

(30].. 4, line 19; ,"abelt" should read a belt-.

line 43; "path" should read "bathline 61, "tothe" should read to the".

Col. 5, line 40 after "trichlorotrifluorobenzene" I insert --describedin U. S. Patent 3,702,534

issued November 14, 197, 2--. line 44; after "Krytox" insert "R" in acircle.

line 45; after "Zonyl" insert "R" in a circle;

Col. 6, line 6; "thisis" should read --this is--.

line 49; "seowri" should read --shown-- Col. 7, line 15; "path" shouldread -'-bath- Signed and sealed this 17th day of Septeinbr 1974,

(SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attes ting Of f icer Connie: ions:of Patents FORM PC4050 (10-69)

1. A rotary closed Rankine cycle engine comprising: a cylindricalhousing rotatable about its axis and including an annular boiler adaptedto contain an annular body of liquid power fluid, means to heat theliquid in the boiler to generate power fluid pressure vapor therein,means subdividing the housing into an expander compartment and lubricantcompartment, an expander in said expander compartment for extractingwork from said pressure vapor including a coaxially rotatable shaftdriven thereby and extending into the lubricant compartment of thehousing, an annular sump in said lubricant compartment adapted tocontain an annular lubricant bath of predetermined radial depth, meansoperable to rotationally drive the housing and boiler about said axis ata predetermined speed to maintain the annular liquid bodies of powerfluid and lubricant in the boiler and sump respectively, pump means inthe lubricant compartment non-rotatable with the housing having alubricant passage extending inwardly from the lubricant bath to saidshaft with the inlet to said passage immersed in the lubricant bath andfacing opposite the direction of rotation of the housing wherebyrotation of said housing relative to said pump means operates to pumplubricant inwardly from the bath through the passage to lubricate saidshaft, and means for heating and vaporizing excess power fluid thatmigrates along the shaft from the expander compartment to the sumpthereby raising the vapor pressure in the lubricant compartmentsubstantially to the vapor pressure in the expander compartment andbalancing the pressure axially along the shaft to prevent furthermigration of power fluid from the expander compartment to the lubricantcompartment of the housing.
 2. A rotary engine as claimed in claim 1wherein the means to rotationally drive the housing and boiler comprisesa fixed-ratio gear train interconnected between the shaft and housingand lubricated by lubricant from the bath.
 3. A rotary engine as claimedin claim 1 wherein bearingS are provided for rotationally supporting theshaft, and passages are provided in said shaft for conducting lubricantfrom the pump means to said bearings for lubricating the bearings.
 4. Arotary engine as claimed in claim 1 wherein the means for heating andvaporizing the excess power fluid migrating to the sump comprises anannular overflow chamber disposed laterally adjacent the lubricant sumpsubstantially at the surface level of the predetermined radial depth ofthe lubricant bath therein for receiving overflow of said lubricant bathcaused by said migration of power fluid to the sump, and means forheating the annular chamber to vaporize power fluid from the overflowlubricant bath therein.
 5. A rotary engine as claimed in claim 4 whereinthe means for heating the annular overflow chamber comprises a secondannular chamber concentrically circumscribing the overflow chamber, andmeans for supplying hot pressure vapor power fluid from the boiler tosaid second chamber.
 6. A rotary engine as claimed in claim 2 whereinthe fixed-ratio gear train includes a plurality of planetary gears, andthe non-rotatable pump means is a stationary member on which saidplanetary gears are rotatably mounted so that the axes of the planetarygears are fixedly positioned circumferentially with respect to therotational axis of the engine.
 7. A rotary engine as claimed in claim 1wherein the non-rotatable pump means comprises a pendulum memberjournalled on the expander shaft and having a density and dimensionsoperable to hold said pendulum member in dependent position and preventrotation thereof about the rotational axis of the engine.